Tobacco product



United States Patent M of Virginia N0 Drawing. Filed Qct. 24, 1962, Ser. No. 232,865 8 Claims. (Qi- 131-17) This invention relates to tobacco products. More particularly it relates to tobacco products which upon smoking have enhanced characteristics of flavor and aroma. it has long been common to alter, enhance and improve the flavor and aroma of tobacco products by incorporating therein by various methods a variety of flavoring and other ingredients. Sugar, licences and other constituents have frequently been used for this purpose, and it has also been suggested to incorporate more uncommon llavorings on the leaf or even to inject them within the living plant. Many aroma and flavor enhancing condiments which confer desirable enhancement of the smoke aerosol when the tobacco product is burned cannot suitably be used by reason of their volatility, instability or other considerations. Such an ingredient is cinnamic acid. Its storage stability has been found to be quite low, and as a result its inclusion in tobacco products at the time of manufacture is not considered worthwhile because the contribution which it makes to the smoke at the time of use by the consumer is greatly diminished.

We have now discovered that cinnamic acid can be contributed to the smoke aerosol upon pyrolysis by incorporating in the tobacco product prior to smoking a small but effective amount of a dimer of cinnamic acid, said dimer being characterized in releasing cinnamic acid below the pyrolysis temperature of tobacco. In particular, we have found that the smoke of tobacco products may be enhanced by incorporating therein at least one member of the group consisting of truxillic acids and tnuxinic acids. a-truxillic acid and ,Btruxinic acid are particularly preferred.

It is known in the art that cinnamic acid polymerizes under irradiation with strong intensity light to its stereoisometric dimers, and particularly to a-truxillic and ptruxinic acids. We have found that cinnarnic acid dimers when incorporated in tobacco products decompose under pyrolytic smoking temperature into cinnamic acid and in some instances small amounts of other substances which are innocuous. The dimers of cinnamic acid are nonvolatile and have no odor and consequently do not contribute undesirable odors to the product during storage or before use. They are stable under storage conditions and are non-reactive. Upon thermal degradation during pyrolysis, however, they release cinnamic acid into the aerosol smoke phase.

The reaction to form dimers of cinnamic acid is known and does not form any part of this invention. The reaction can be illustrated as follows:

2flrH CH=CHOOOH CsHsCHCHCOOH cinuamic acid H O O C O HCHCsH a-truxillic acid H OH=CHG 0 OH CnHsCHCHC O OH CaHsCHCHC O OH B-truxinlc acid (fi-isotruxillic acid) cinnamic acid 3,1 1 1,951 Patented Nov. 26, 1963 limitativeof the invention and that by ltr-uxillic acids we mean any of the isomeric forms of the 2,4-diphenylcyclobutane-l,3-dicarboxylic acids, including the truxin-ic acids, by which we mean any of the corresponding 3,4- dipnenyl-1,2-dicarboxylic acids.

The presence in the smoke aerosol in small but eifective amounts of oinnamic acid in either its ois or trans forms contributes a subtle and desirable flavor and aroma of cinnamon to the smoke. The amounts of dimer incorporated in the tobacco product is not critical and may be selected by one skilled in the act according to the subtlety or distinctness of the cinnamon note desired to be imparted, and the amount may well be related to the nature and amounts of other flavoring or aroma-producing constituents in a particular mix. Generally, We have found that from about 1 to about 10" mg. of dimer per gram of tobacco product is a desirable and appropriate range.

Derivatives of cinnamic acid which are characterized in imparting flavor and/ or aroma to smoke may also be incorporated in tobacco products in the form of their dimers in accordance with the invention. Illustrative derivatives include the lower alkyl (up to about 6 carbon atoms) and aryl esters of cinnamic acid. Diinors of the methyl, ethyl and benzyl esters of cinnarnic acid are particularly preferred.

The following examples are intended to be illustrative of the invention and are not to be taken in a limiting sense. All parts are by weight except as otherwise specified.

Example 1 Trans-cinnamic acid is irradiated for hours under a General Electric HBF high pressure mercury arc lamp giving strong radiation at 290 mg. The product is dried in a desiccator and analyzed on a Cary 11 spectrophotometer. None of the starting material is identified as present in the product. Photodimerization is found to have taken place with the formation of a-ctruxillic and t?- truxinic acids as the greatly predominant products.

2 grams of the product is pyrolyzed in a 30 X 180 mm. Vycor t-ube packed With porcelain saddles and heated in an electric furnace, under the following reaction conditions: nitrogen flow 600 ml. per second, residence time 3 seconds, reaction temperature 500 0:10, rate of addition 0.10 g. per minute. A yield of 1.38 g. of crude pyrolysis product is collected in a trap cooled by Dry Iceacetone and is dissolved in ether and esterified with ethereal diazornethane. The methylated solution is examined by gas chromatography, using an F&M model 500 instrument with a 2 foot X inch column of 20% Carbowax on firebrick, column temperature C., carrier gas ilow rate 68 ml. per minute.

Only three peaks are observed on the chromatograrn. The three components are identified by trapping the exit gases corresponding to each peak and measuring the ultraviolet absorption spectrum of the methanol solutions. The three pyrolysis products are thus identified as cis-cinnarnic acid, trans-einnamic acid and cis-stilbene. The identifications are confirmed by comparing the chromatographic retention times of known reference samples of these three products with the retention times of the pyrolysis products. The yields from the two gram sample of u-truxill-ic acid and fi-truxinic acid mixture are calculated from the areas under the peaks of the gas chromatogram using calibration curves prepared from known reference samples as follows:

Tr-ans-cinnarnic acid 1.0 5 Cis-cinnamic acid 0.17 Cis-stilbene 0.01

'3 Example 2 Regular cigarette filler is sprayed with 4% corn syrup and divided into two parts, one being a control. To the other portion is added the photodimerization product tained in Example 1, with mixing in a Blender. It made cigarettes are then prepared from both batches, cigarettes weighing 1.2 grams each and the test group containing 1 mg. of the mixed truxillic acid dimers.

The cigarettes are smoked in a machine under standard conditions (70 mm. cigarettes smoked to a mm. butt at cc. volume puffs of 2-second duration at intervals of one puff per minute). The smoke from the cigarettes is collected in a gas phase collection smoking machine at liquid nitrogen temperature and analyzed spectrophotometrically. The smoke of the test cigarettes is found to contain significant amounts of cinnarnic acid. All the other smoke components are substantially the same in both the test and control cigarettes. The amount of cinnamic acid transferred to the smoke aerosol phase of the test cigarettes ranges from 14 to 197 (micrograms) per cigarette, the average being 17 per cigarette. T he smoke from the controls contains no cinnamic acid.

Subjective tests of the two groups of cigarettes by a panel of smokers shows that the groups are readily distinguishable and that a definite and pleasing flavor of cinnamon is detected in the smoke of the test cigarettes.

Example 5' Example 4 Ethyl cinnamate is irradiated at room temperature for hours according to the procedure of Example 1. Analysis of the product shows it to be substantially ethyl OL-tFUXilIZIte (melting point 144-146 C.).

The ester is pyrolyzed at 500 C. according to the procedure of Example 1. The liquid pyrolysate, obtained in a yield of is examined by gas chromatography with a 10 ft. Carbowax column at 200 C. Two peaks are observed in the curve andthe corresponding components are separately collected in traps. The principal component comprising about of the pyrolysate 1s identified by infrared and ultraviolet spectroscopy as ethyl trans-cinnamate; the minor component comprising about 10% of the mixture is similarly identified as ethyl cis-oinnamate. No other pyrolysis products are observed.

Test cigarettes containing between 1 and 10 milligrams each of ethyl a-trux-illate are smoked by a panel of smokers and a pleasing cinnamon-type note, distinct from that of the test cigarettes of the foregoing examples, is detected.

Example 5 Dimers of lower alkyl esters of cinnamic acid and dimers of aryl esters of cinnamic acid are prepared and incorporated in cigarettes in amounts between about 1 and 10 milligrams per cigarette. Pleasing flavor notes are detected in the smoke or" the cigarettes so prepared.

it is to be understood that dimers of cinnamic acid and its alkyl and aryl derivatives may be employed in accordance with the invention without regard to the manner of their preparation and that the invention does not depend upon the preparative steps hereinabove described. Mixtures of such dimers may be incorporated in tobacco products, and they may be blended with still other flavorings in manners known to the art.

We claim:

1. A tobacco product having incorporated therein a dimer of a member of the group consisting of cinnamic acid and its lower alkyl and aryl derivatives.

2. A tobacco product according to claim 1 wherein the amount of dimer is between about 1-10 mg. per gram of tobacco product.

3. A tobacco product having incorporated therein a member of the group consisting of a truxillic acid and the lower alkyl and aryl esters thereof.

4. A tobacco product having incorporated therein a member of the group consisting of 2,4-diphenylcyclobutane-1,3-dicarboxylic acids, the corresponding 3,4-diphenyl-l,2-dicarboxylic acids and the lower alkyl and aryl esters of said acids.

5. A tobacco product having incorporated therein atruxillic acid.

6. A tobacco product having incorporated therein ,8- truxinic acid.

7. A method of enhancing the flavor of the smoke of a tobacco product, which comprises incorporating with said tobacco product prior to smoking a small but efl'ective amount of a dimer of a member of the group consisting of cinnamic acid and its lower alkyl and aryl derivatives.

8. A method according to claim 7, wherein the amount of said dimer is between about 1-10 mg. per gram of tobacco product.

No references cited. 

4. A TOBACCO PRODUCT HAVING INCORPORATED THEREIN A MEMBER OF THE GROUP CONSISTING OF 2,4-DIPHENYLCYCLOBUTANE-1,3-DICARBOXYLIC ACIDS, THE CORRESPONGING 3,4-DIPHENYL-1,2-DICARBOXYLIC ACIDS AND THE LOWER ALKYL AND ARYL ESTERS OF SAID ACIDS. 